In Float, there is an class var named Epsilon (1.0e-12 in my image). Method initialize in the class side of Float is interesting by the way... So Epsilon := 0.000000000001. "Defines precision of mathematical functions" is set when the class is inittialized.
Just for information, is it possible to set this value at image startup depending on the architecture ?
So ok we forget that... Perfectly explained :)